Apparatus for refining metals

ABSTRACT

An apparatus for refining metals having a vacuum chamber for receiving the refined metal and provided with a central longitudinal column surrounded by a cylindrical multilayer perforated screen and evaporating plates. A heater is mounted along the column axis and is provided with cooled current feeders. In the bottom portion of the cylindrical vacuum chamber of the apparatus there is positioned a condensate collector. The condensate collector represents a cylindrical vessel mounted coaxially with the vacuum chamber and having a conical upper portion. The current feeders of the heater are mounted in the lower portion of the vacuum chamber and connected with the heater through graphite rods penetrating through the cylindrical wall of the condensate collector.

United States Patent .1191

Esjutin et al.

[ APPARATUS FOR REF INING METALS [76] lnventors: Vladimir SergeevichEsjutin, M.

Tulebaeva ulitsa, 187, kv. 4; Zhavdat Sharafutdinovich Taziev, ulitsaTimiryazeva, 97, kv. 29; Sergei Julievich Senjuta, ulitsa Dzhandosova,164, kv. l7; lbragim Abilgazievich Onaev, ulitsa Kalinina, 65, kv.- 23,all of Alma-Ata; Serafim Nikolaevich Suturin, ulitsa Savvy Kozhevnikova,2, kv. 22, Novosibirsk; Demyan lllarionovich Gavrilenko, ulitsa Dolgaya,30, Odessa; Nikolai Stepanovich Kleschenko, ulitsa 3 Olovozavodskaya, 8,kv. l l, Novosibirsk; Nikolai Arsenievich Voronkov, ulitsa Anikina, 21,kv.

' l2, Novosibirsk; Alexei Fedorovich Raznitsyn, ulitsa Sovetskaya, 7,kv. l 12, Novosibirsk; Semen Alexeevich Ryzhkin, ulitsa 2Olovozavodskaya, l6, kv. l2, Novosibirsk; Alexei Alexeevich Klevakin,ulitsa 2 Obogatitelnaya, l 1, kv. 6, Novosibirsk; Alexandr EfimovichSemenov, ulitsa Zorge, 133, kv. 33, Novosibirsk; Alexandr StepanovichIvannikov, ulitsa Nekrasova, 3, Krymskaya' Oblast; Vladimir SemenovichCherednichenko, ulitsa R. Zorge, 181, kv. 108, Novosibirsk; Gennadylvanovich Orlov, ulitsa Vatutina, 27, kv. 20, Novosibirsk; JuryAnatolievich Naryshkin, ulitsa Bljukhera, 7, kv. 55, Novosibirsk; JuryPetrovich Novikov, ulitsa Vertkovskogo, l4, Novosibirsk, all 7 14 1 Apr.9, 1974 22 Filed: Nov. 27, 1972 211 App]. No.: 309,933

Primary Examiner-Roy N. Envall, Jr. Attorney, Agent, or Firm-Holman &Stern [57] ABSTRACT An apparatus for refining metals having a vacuumchamber for receiving the refined metal and provided with a centrallongitudinal columnsurrounded by a cylindrical multilayer perforatedscreen and evaporating plates. A heater is mounted along the column axisand is provided with cooled current feeders. In the bottom portion ofthe cylindrical vacuum chamber of the apparatus there is positioned acondensate collector. The condensate collector represents a cylindricalvessel mounted coaxially with the vacuum chamber and having a conicalupper portion. The current feed- ,ers of the heater are mounted in thelower portion of the vacuum chamber and connected with the heaterthrough, graphite rods penetrating through the cylindrical wall of thecondensate collector.

2 Claims, 2 Drawing Figures PATENIEDAPR .9 I974 3.803335 SHEET 1 [IF 2BACKGROUND OF THE INVENTION The present invention relates to therefinement of metals, and more particularly to continuous-operatingapparatus for refining non-ferrous metals.

Known in the art is an apparatus for the continuous refinement of metalsthrough the distillation of lowboiling impurities from the alloys beingrefined in a vacuum plate column having a central heater, which columnis surrounded with a multy-layer perforated screen and provided withbarometric metal conduits to supply the metal to the apparatus and todischarge the distillation products therefrom.

The disadvantage of the known apparatus is in the constructivecomplexity and unreliability of the discharge unit for the liquidcondensate and in the current-supplying network to the heater, whichleads to increased electric power consumption during the refinementprocess.

Additionally, the known apparatus is unable to provide a durable andcontinuous refinement of metals and has a comparatively loweffectiveness.

SUMMARY OF THE INVENTION An object of the present invention is toimprove the construction of apparatus for refining metals which providesa durable and continuous operation.

Another object of the invention is to increase the specificeffectiveness of the refinement process and to improve the quality ofthe obtained metal.

These and other objects of the invention are achieved by providing anapparatus for refining metals through the distillation of low-boilingimprurities in a vacuum, comprising a cylindrical vacuum chamber with acolumn longitudinally mounted therein which is surrounded with acylindrical multi-layer perforated screen and has open evaporatingplates and a heater mounted along the column axis and provided withcooled current feeders, a condensate collector which is mounted in thebottom portion of the vacuum chamber and connected with a metal conduitfor discharging the condensate, and a cooling means mounted under thevacuum chamber and having a metal conduit for discharging the refinedmetal, wherein, according to the invention, the condensate collectorrepresents a cylindrical vessel coaxially mounted with respect to thevacuum chamber and having a conical upper portion which houses a part ofthe heater, the current feeders being mounted in the lower part of theside wall of the vacuum chamber and connected with the heater by meansof graphite rods penetrating through the cylindrical wall of thecondensate collector.

Such a construction of the apparatus provides for a durable andcontinuous operation and makes it possible to increase the specificefficiency of the refinement process with a consequent improved qualityof the obtained metal.

BRIEF DESCRIPTION OF THE INVENTION The following example illustrates thespecific embodiment of the apparatus for refining tin from lead andbismuth according to the invention with reference to the accompanyingdrawings, wherein:

FIG. 1 is a longitudinal section of the apparatus according to thepresent invention;

FIG. 2 is a cross-section on II-II of FIG. 1.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS The apparatus consists ofa cylindrical vacuum chamber l, a cover 2 and a bottom 3.

Inside of the chamber 1 there are mounted annular plates 4 for apreliminary heating of the metal being refined, and plates 5 mounted onthe base 6 one above the other for evaporating impurities from themetal. The plates 4 and 5 are manufactured from an electrode-gradegraphite.

Each of the plates 4 and 5 is provided with an annular groove for theflow of the metal being refined. Each of the plates 4 and 5 has abranch-pipe with an opening for discharging the metal to a subsequentlower plate. Each of the branch-pipes is so disposed as to provide onthe plate a certain metal layer. The four upper plates 4 are closed andare designed for heating the initial metal being charged into theapparatus for heating the initial metal being charged into the apparatusup to the temperature which provides an intensive evaporation of thelow-boiling impurities. The plates 4 and 5 are made of electrode-gradegraphite. The plates 4 are heated by a graphite heater 7. The graphiteheater 7 represents a rod positioned in the inner space of the annularplates 4 and 5 and having a longitudinal slot and a thickening in itslower part designed for connecting the heater with current feeders 8.The heater 7 is fixed and fed with electric power in the following way:into the lower thickened part of the heater 7 there are screwed threadedgraphite rods 9, into which there are in turn screwed the water-cooledcopper currentfeeders 8 provided with an electric insulator 10.

Inside of the working space of the chamber 1, be tween the plates 4 and5 and the walls of the chamber 1, there are mounted heat-insulatingscreens 11 and 12 representing perforated cylinders which are used toreduce the heat losses and to provide a partial condensation of metalvapours.

A part of the screens 11 positioned in the zone of high temperatures andaggressive vapours of tin is manufactured from graphite. The screens 12mounted nearby the walls of the chamber 1 are made of sheet steel. Allthe screens 11 and 12 have inter-overlapping openings 13 disposed in achess order to pass metal vapours to the condensation zone. All thescreens 11 and 12 are provided with covers 14 which are also made withperforations.

To form condensate of the vapours of volatile impurities in a liquidstate, inside of the chamber 1 there is mounted a cylindrical condenser15 provided with a cover and made of steel.

In the bottom part of the vacuum chamber 1 there is positioned acondensate collector 16.

The condensate collector 16 represents a cylindrical vessel positionedcoaxially with respect to the vacuum chamber 1 and having a conicalupper portion 17.

In the cylindrical portion of the collector 16 there is disposed thelower part of the heater 7.

The collector 16 is made of steel and protected from the action of theliquid condensate with a graphite lining 18.

On the lining 18 of the conical portion 17 of the collector 16 thererests the base 6 of the plates 4 and 5. The lower part of the collector16 is connected with a metal conduit 19 similarly lined with graphiteand designed for discharging the condensate.

The conical portion 17 of the collector 16 is provided with an openingfor a graphite pipe 20 which is used to discharge the refined metal fromthe lower evaporating plates through a graphite pipe 21 into a coolingmeans 22 to reduce the temperature of tin from l,300C up to 350-300C.Besides, the walls of the collector 16 serve as an additional condenser.

The cooling means 22 represents a set of graphite plates 25 housed in ametal cylindrical casing 26. The plates are cooled by means of a coiledpipe 27 mounted at the outer side of the casing 26 and fed with water orair. The pouring of the refined metal and the condensate is accomplishedfrom ladles 28 and 29.

The heating network of the metal conduit 24 and the ladle 28 is switchedon only at the begining of the operation and then it is switched out,since the metal flow from the apparatus maintains the necessarytemperature.

The apparatus operates as follows. The tin being refined from lead andbismuth is fed through the metal conduit 23 to the upper plate 4 andheated in the first four closed plates up to a temperature from 1,200 to1,350C at which lead and bismuth start evaporating. Then the tinsuccessively flows on the evaporating plates 5. Due to a residualpressure in the apparatus, the lead and the bismuth contained in the tinare gradually evaporated while the tin flows down on the plates 5. Therefined tin is fed from the lower plate 5 through the graphite pipes and21 to the cooling means 22, where the tin flows on the cooled plates 25,its temperature dropping to 350400C, then it is decanted into the ladle28 and therefrom it is distributed into pigs. The vapours of lead andbismuth and partly of tin are primarily condensated in the liquid stateon the screens 11 and 12 and partly on the condenser 15, therefrom thevapours flow down into the collector 16. From the collector 16 theliquid condensate is fed to the metal conduit 19 and then it isdischarged into the ladle 29. Therefrom the condensate is distributedinto pigs.

In the tests of the present apparatus for refining tin the followingtechnological data have been achieved.

The contents of lead and bismuth may be reduced from the initial amountsof about l.5l.l weight per cent and 0.3-0.1 weight per cent in black tinto about 0.04-0.02 weight per cent and 0.01-0.005 weight per cent,respectively, at a temperature between about l,300 to 1,350C and aresidual pressure in the chamber of about 0. 1-0.3 mm Hg. The dailyefficiency of'the vacuum apparatus is about 14-18 tons of tin per squaremeter of the evaporating surface of the plates. In the refining of blacktin with the use of the apparatus according to the invention, the directrecovery of tin is not less than about 98-99 weight per cent of puremetal.

The condensate contains about 50-60 weight per cent of tin. Theremainder involves lead and bismuth depending on their contents in theinitial black tin.

The construction of an apparatus for refining metals in accordance withthe present invention may provide a reliable operation of the apparatusand an increased specific efficiency thereof. Besides, it may provide animprovement in the quality of the obtained metal and a reduction of theinvenstments of the production.

What is claimed is:

1. An apparatus for refining metals by vacuum distillation oflow-boiling impurities from a melt, comprising: a vertical cylindricalvacuum chamber; column means mounted in said chamber substantially alongthe central axis thereof, said column means having a plurality ofintercommunicating evaporating plates disposed stackwise along its axiswhereby unrefined metal melt delivered to an upper one of said platesmoves successively to a lower one thereof; a multilayer perforatedcylindrical screen substantially concentrically disposed around saidcolumn means in said vacuum chamber for condensing thereon vapors of theimpurities of the melt contained in said evaporating plates; acondensate collector means for collecting the condensate formed on saidscreen and positioned in the lower part of said vacuum chamber coaxiallytherewith, said condensate collector means comprising substantially acylindrical vessel having a metal conduit connected to its lower end forpermitting egress of said condensate therefrom and a funnel-shaped upperportion which faces the direction of the incoming condensate from saidscreen, connected to its upper end; a heater mounted along the axis ofsaid column means for heating said unrefined metal delivered to saidevaporating plates and causing said' vapors of the impurities of themelt to be condensed on said screen, said heater having a lower portionlocated in the upper portion of said cylindrical vessel; a plurality ofcurrent feeders mounted in the lower part of the side wall of saidvacuum chamber; a plurality of electrically insulated graphite rodsoperatively connected to said lower portion of said heater and passingexteriorly of said condensate collector means substantially at the upperportion thereof, and operatively connecting respective ones of saidplurality of current 1 delivery from its lower end to a ladle.

1. An apparatus for refining metals by vacuum distillation oflow-boiling impurities from a melt, comprising: a vertical cylindricalvacuum chamber; column means mounted in said chamber substantially alongthe central axis thereof, said column means having a plurality ofintercommunicating evaporating plates disposed stackwise along its axiswhereby unrefined metal melt delivered to an upper one of said platesmoves successively to a lower one thereof; a multilayer perforatedcylindrical screen substantially concentrically disposed around saidcolumn means in said vacuum chamber for condensing thereon vapors of theimpurities of the melt contained in said evaporating plates; acondensate collector means for collecting the condensate formed on saidscreen and positioned in the lower part of said vacuum chamber coaxiallytherewith, said condensate collector means comprising substantially acylindrical vessel having a metal conduit connected to its lower end forpermitting egress of said condensate therefrom and a funnel-shaped upperportion which faces the direction of the incoming condensate from saidscreen, connected to its upper end; a heater mounted along the axis ofsaid column means for heating said unrefined metal delivered to saidevaporating plates and causing said vapors of the impurities of the meltto be condensed on said screen, said heater having a lower portionlocated in the upper portion of said cylindrical vessel; a plurality ofcurrent feeders mounted in the lower part of the side wall of saidvacuum chamber; a plurality of electrically insulated graphite rodsoperatively connected to said lower portion of said heater and passingexteriorly of said condensate collector means substantially at the upperportion thereof, and operatively connecting respective ones of saidplurality of current feeders with said lower portion of said heater; andmeans operatively associated with said vacuum chamber for cooling andcollecting refined metal delivered from said evaporating plates aftersaid vapors have been evaporated from the unrefined melt deliveredthereto.
 2. Apparatus as defined in claim 1 wherein said means forcooling and collecting refined metal includes cooling means having anupper end connected to said lower one of said plurality of evaporatingplates for drawing off the refined metal therefrom, said cooling meansappropriately cooling said refined metal prior to delivery from itslower end to a ladle.